Types to Try
Spinach varieties vary in the size, shape and texture of the leaves.
Savoyed and semi-savoyed types have dark green leaves — that are puckered or crinkled — and become especially crisp in cold weather. Many of the best varieties for growing through winter have savoyed leaves.
Smooth-leafed spinach is often a lighter shade of green compared to savoyed spinach, but the leaves are easier to wash and the plants tend to grow upright. Fast and easy to grow, smooth-leafed spinach can be gathered as baby greens, or you can let the plants grow to mature size.
When to Plant
In late winter, beginning six weeks before your average last spring frost date, start seeds indoors or beneath a protective frame outdoors. Make two additional spring sowings at three-week intervals.
In summer, skip spinach and try the warm-weather alternatives.
In fall, six to seven weeks before your first fall frost date, sow your main crop for fall harvest.
About four weeks before your first fall frost date, sow winter spinach in a place where the seedlings can be covered in frigid weather with glass, plastic or a thick row cover. This planting will mature in early spring.
How to Plant
Prepare the planting bed by loosening the soil at least 10 inches deep. Thoroughly mix in compost along with alfalfa meal, soybean meal or another high-nitrogen organic fertilizer (follow label directions). Sow seeds a half-inch deep and 2 inches apart, in rows spaced at least 8 inches apart. As the plants grow, gradually thin them so the leaves of neighboring plants barely overlap.
Harvesting and Storage
Beginning about six weeks after planting, pinch off individual leaves as you need them in the kitchen, leaving the central rosette intact.
In spring, long, warm days cause spinach to “bolt” (flower and produce seeds). Unless you plan to save seeds, pull up the plants when you notice them developing a tall central stem. Thoroughly clean, then steam-blanch (which limits their uptake of water and fixes enzymes) and freeze bumper crops.
Spinach is pollinated by wind, so select a group of closely spaced plants to get seed from an open-pollinated variety. Spinach plants can be male or female. Male plants quickly grow tall and release pollen from clusters of fringelike structures, while females are stockier and hold their flower clusters close to the main stem. If you save seeds, allow seed-bearing plants to stand in the garden until they begin to dry.
In wet weather, pull them up and let them finish drying in a warm, well-ventilated place. Strip the seeds from the plants and let them air dry for a few days before cleaning and sorting them. Store in a cool, dark place for up to three years. When placed atop hospitable soil, seed-bearing plants often shed enough seed to start a fall crop.
Hybrid spinach varieties such as ‘Tyee’ (savoyed) and ‘Space’ (smooth-leaf) deliver high levels of disease resistance, but homegrown spinach rarely faces serious disease pressure. Among open-pollinated varieties, ‘Monnopa’ and ‘Butterflay’ are lower in oxalic acid compared to other varieties, which gives them a mild, sweet flavor. ‘Giant Winter’ and ‘Monstrueux de Viroflay’ produce leaves twice the size of regular spinach.
Spinach Pest and Disease Prevention Tips
Keep plants widely spaced to help prevent problems that are encouraged by moist conditions, such as slugs and mildew diseases.
Avoid growing spinach where beets or chard were grown in the previous season. These crops are closely related to spinach, make similar demands on the soil and host the same soilborne diseases.
Gently squash leaf miners with your fingers or remove infested leaves. Spinach leaf miners are the larvae of small flies that make meandering pale tunnels as they feed inside spinach leaves. Where pressure is serious, use row covers to exclude the flies.
Pull back mulch to limit slug habitat, and trap them under boards or with beer-baited pit traps. Slugs make holes with clean edges in spinach leaves.
Pull up plants that show distorted new growth accompanied by yellowing of older leaves. Aphids and leafhoppers can transmit viral diseases to spinach.
Hybrids offer genetic resistance against downy mildew. Especially in the Southeast, downy mildew causes gray patches on affected leaves.
Fertilize overwintered plants with a thorough drench of a fish-based fertilizer after they show new growth in spring. In spring, spinach often starts growing before the soil is warm enough to release enough nitrogen to meet the plants’ needs. Spinach requires soil with a near-neutral pH, and germinates best when the soil ranges between 55 and 65 degrees.
Clip off old leaves as they turn yellow to reduce demands on the plant for nutrients and moisture.
Wait for frost to harvest your main fall crop. Exposure to cold increases the production of sugars in spinach leaves, which serve as natural antifreeze and taste great.
Use frames or tunnels to protect winter spinach from accumulated ice and snow as far north as Zone 4. Plants that receive winter protection will begin growing again early in the spring.
In the Kitchen
Fresh from the garden, spinach is loaded with vitamins A and C, calcium and iron, and it has a remarkably buttery, nutty flavor when eaten raw in salads or sandwiches. Try semi-cooked wilted spinach salads made by pouring hot dressing over a bowl of torn spinach. Sage or thyme make great flavor accents. (Any dish with “Florentine” in its name includes cooked spinach.)
Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on Google+.